pittrek said:

What are the 2011 Blurays?

Something like : Original negatives -> 1995 scan -> SE digital version -> 1997 SE prints -> 1080p scan with colour "correction" -> Lowry "restoration" -> 1080p DVD master -> more stupid digital changes -> 2011 Bluray master

So yes, the BDs are done from an early century 1080p scans of SE masters, but no, they didn't do it because "original negatives are nowhere to be found" but simply because GL for some reason considered the old horrible looking scans to be "good enough" and didn't want to spend money for doing it correctly.

Even if the rumours that the original negatives were modified to contain 1997 SE material (which I doubt, I simply refuse to believe they were THAT stupid), they still have finished prints of the original theatrical editions (including some Technicolor prints if I remember correctly). Even scanning these prints would be "good enough" for most of us

I think it's been documented that the o-neg was in fact re-conformed for the SE. That is why they were able to just scan it in '04 and all the '97 changes were already there. If you look closely, you can still see some filmic anamolies in the cgi shots from '97, even after Lowry's cleanup job. This leads me to believe that the filmed-out negative is the best surviving source for the '97 cg shots and that the final 2k renders were not saved on hard drives at ILM or Lucasfilm.